Y 2 O 3 :Eu 3+ @SiO 2 nanocomposites as a convertor for a broadband solar‐blind UV photodetector

Core–shell nanocomposites have attracted extensive attention in the photoelectric field because of their improved material properties and the combination of multiple functions. Particularly, these nanocomposites exhibit tunable structure and excellent optical properties. Inspired by these unique features, a novel optically active nanocomposites, Y 2 O 3 :Eu 3+ @SiO 2 with a core–shell structure, is designed and fabricated by a hydrothermal method and electrophoretic deposition. In addition, the Y 2 O 3 :Eu 3+ @SiO 2 composite film is also successfully developed and applied as a spectral down‐converter in the solar‐blind ultraviolet (UV) waveband region of 200–280 nm. Moreover, a broadband solar‐blind UV photodetector device is elaborated and a notable enhancement in the UV sensitivity is achieved. The findings not only provide a new idea for the development of broadband solar‐blind UV photodetector but also extended the application range of core–shell nanocomposites in photonics.